1. Field of the Invention
The present invention relates to exercise machines that exercise different muscle groups. More particularly, the present invention relates to exercise machines that exercise the deltoid muscle groups.
2. Prior Art Statement
It is well known by bodybuilders, trainers and physical therapists, that the best way to train a particular muscle group is to isolate that particular muscle group when exercising. By isolating a particular muscle group during exercise, the strength of that muscle group can be accurately assessed and tracked. Furthermore, by isolating a particular muscle group during exercise, other surrounding muscle groups are prevented from performing the work of the targeted muscle group. The work contributed by the untargeted muscle groups are therefore minimized. In this manner, by isolating a targeted muscle group that is weak, undersized, or damaged, that targeted muscle group can be made to be made stronger in an efficient manner.
The deltoid muscle group is one of the muscle groups surrounding the shoulders of the arms. The deltoid muscle group includes the posterior deltoid muscles, the lateral deltoid muscles and the anterior deltoid muscles. The posterior deltoid muscles are the muscles used to extends the arms behind the body. The lateral deltoid muscles are the muscles that move the arms outwardly from the sides of the body. The anterior deltoid muscles are the muscles used to raise the arms in front of the body.
The muscles of the deltoids are some of the hardest muscles to isolate when exercising. Since the deltoids control movement of the arms around the shoulder joints, it is difficult to isolate the deltoid muscles and exercise the deltoid muscles without having the muscles of the arm assist in the exercise movement.
The prior art is replete with different types and styles of exercise machines. Many of these machines enable a person to exercise different muscle groups. Some exercise machines and devices isolate the posterior and/or lateral deltoid muscles. For example, U.S. Pat. No. 5,171,198 to Jones, entitled Lateral Raise Exercise Machine and U.S. Pat. No. 5,540,640 to Povilaitis, entitled Deltoid Muscle Exercise Device, both show exercise devices that resist the arms from moving outwardly from the sides of the body. Consequently, both these exercise devices exercise the lateral deltoid muscle groups.
However, it is much harder to create exercise machines that isolate the anterior deltoid muscles. The anterior deltoid muscles are used to raise the arms forward. Most all exercise machines that resist the arms in being raised forward contain handles that are grasped by the hands. Since resistance is being applied to the arms through the hands, it is inevitable that the various muscles contained within the hands, wrists and arms will also act to move the arms against the applied resistance. As a result, the anterior deltoid muscles are exercised with the assistance of other muscles and the anterior deltoid muscles are not themselves well isolated. Prior art exercise machines that exercise the anterior deltoid muscles along with other muscle groups in the arms and chest are exemplified by U.S. Pat. No. 5,931,767 to Morales.
A need therefore exists in the prior art for an exercise machine that isolates the anterior deltoid muscles and exercises the anterior deltoid muscles without having to involve the other major muscle groups in the arms. This need is met by the present invention as described and claimed below.